Semiconductor components, such as bare dice, chip scale packages, BGA devices and wafers can include terminal contacts in the form of contact balls. This type of component is sometimes referred to as a “bumped” component (e.g., bumped die, bumped wafer).
The contact balls provide a high input/output capability for a component, and permit the component to be surface mounted, or alternately flip chip mounted, to a mating substrate, such as a printed circuit board (PCB). Typically, the contact balls comprise solder, which permits bonding to the mating substrate using a solder reflow process. For some components, such as chip scale packages and BGA devices, the contact balls can be arranged in a dense array, such as a ball grid array (BGA), or a fine ball grid array (FBGA).
One problem with solder contact balls is that solder is a relatively soft material, and the balls deform easily during handling and testing of the components. During testing, the component is typically inserted into a test socket having electrical connectors, such as spring loaded pins (e.g., “POGO PINS”), that electrically engage the contact balls. Because solder is a soft material, the electrical connectors on the test socket can deform the contact balls on the components. This problem is compounded during testing at elevated temperatures, such as burn-in testing, as heating further softens the solder.
For performing subsequent test procedures, it may be difficult to make low resistance electrical connections with deformed contact balls. In particular, the electrical connectors on the test apparatus may not adequately engage the surfaces of the contact balls. Also, for subsequent bonding procedures, deformed balls can make alignment and bonding of the component with a mating substrate more difficult to perform. In addition, deformed contact balls are a cosmetic problem that can affect a users perception of a semiconductor component.
In addition to making electrical connections for test procedures more difficult, deformed contact balls can alter test results by affecting electrical characteristics, such as contact resistance, inductance, and signal speed during the test procedure. Further, solder readily oxidizes, which adds resistance to the electrical connections with the contact balls.
Another problem with solder contact balls is the adverse affect that solder can have on a semiconductor test system. For example, solder flakes can break loose from the balls, contaminating test sockets, and other electrical components associated with the test system. This can change the calibration of the test system and affect test results on all of the components being tested. In addition, solder is a contaminant to other semiconductor fabrication processes, and its presence requires special handling and segregation of the components. For some components, technicians may be required to wear gloves, and other protective clothing, to prevent lead from being deposited on their skin.
In view of the foregoing, it would be advantageous to provide a test carrier for temporarily packaging bumped semiconductor components in which contact balls on the components are protected during test procedures. In addition, it would be advantageous to provide a calibration carrier for calibrating, and a cleaning carrier for cleaning, test systems for bumped semiconductor components.